Customized patient-specific acetabular orthopaedic surgical instrument and method of use and fabrication

ABSTRACT

A customized patient-specific orthopaedic instrument for facilitating implantation of an acetabular cup prosthesis in a coxal bone of a patient includes a customized patient-specific acetabular reaming guide. The customized patient-specific acetabular reaming guide includes a longitudinal passageway for an acetabular reamer and a plurality of arms with attached feet. Each foot of the reaming guide is positioned relative to the body based on the contours of the coxal bone of the patient and a predetermined degree of version and inclination angles of the acetabular cup prosthesis when implanted in the patient&#39;s coxal bone.

CROSS-REFERENCE TO RELATED U.S. PATENT APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Patent Application Ser. No. 61/101,524 entitled “CustomizedPatient-specific Acetabular Orthopaedic Surgical Instrument and Methodof Fabrication,” by Ryan Keefer, which was filed on Sep. 30, 2008, theentirety of which is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates generally to customized patient-specificorthopaedic surgical instruments and more particularly to customizedpatient-specific acetabular orthopaedic surgical instruments.

BACKGROUND

Joint arthroplasty is a well-known surgical procedure by which adiseased and/or damaged natural joint is replaced by a prosthetic joint.For example, in a hip arthroplasty surgical procedure, a prosthetic hipreplaces a patient's natural hip. A typical prosthetic hip includes anacetabular orthopaedic prosthesis and/or femoral head orthopaedicprosthesis. A typical acetabular orthopaedic prosthesis includes anacetabular cup, which is secured to the patient's natural acetabulum,and an associated polymer bearing or ring.

To facilitate the replacement of the natural joint with an acetabularorthopaedic prosthesis, orthopaedic surgeons may use a variety oforthopaedic surgical instruments such as, for example, reamers, drillguides, drills, and/or other surgical instruments. Typically, suchorthopaedic surgical instruments are generic with respect to the patientsuch that the same orthopaedic surgical instrument may be used on anumber of different patients during similar orthopaedic surgicalprocedures.

SUMMARY

According to one aspect, a customized patient-specific orthopaedicinstrument for facilitating implantation of an acetabular cup prosthesisin a coxal bone of a patient may include a customized patient-specificacetabular reaming guide. The customized patient-specific acetabularreaming guide may include a body having a longitudinal passagewaydefined therethrough. The customized patient-specific acetabular reamingguide may also include a plurality of arms extending from the body.Additionally, the customized patient-specific acetabular reaming guidemay include a plurality of feet configured to contact a coxal bone of apatient. Each foot of the plurality of feet may be coupled to acorresponding arm of the plurality of arms. Additionally, each foot ofthe plurality of feet may be positioned relative to the body based on apredetermined degree of version and inclination angles of the acetabularcup prosthesis when implanted in the patient's coxal bone and on thecontour of the coxal bone of the patient.

In some embodiments, each foot of the plurality of feet may include abottom, bone-facing surface having a customized patient-specificnegative contour configured to receive a portion of the patient's coxalbone having a corresponding positive contour. Additionally, in someembodiments, the longitudinal passageway of the body may be sized toreceive a bone guide pin. Alternatively, the longitudinal passageway ofthe body may be sized to receive a body of an acetabular reamer surgicaltool.

In some embodiments, the body may include a bottom, bone-facing surfaceand each foot of the plurality of feet may include a top surface. Thebottom, bone-facing surface of the body may be coplanar or non-coplanarwith respect to a plane defined by the top surface of least one of theplurality of feet. In some embodiments, the plurality of feet includes afirst foot having a first top surface defining a first plane and asecond foot having a second top surface defining a second plane. In suchembodiments, the bottom, bone-facing surface of the body, the first topsurface, and the second top surface may be parallel and non-coplanarwith respect to each other. Additionally, in some embodiments, each footof the plurality of feet may include a bottom surface. The bottom,bone-facing surface of the body may positioned medially with respect tothe bottom surface of each foot of the plurality of feet when thecustomized patient-specific acetabular reaming guide is positioned incontact with the patient's coxal bone.

Additionally, in some embodiments, each foot of the plurality of feetmay have a longitudinal length substantially different from each other.The body may also include a sidewall and each arm of the plurality ofarms may include a bottom surface. Each bottom surface of the pluralityof arms may define an angle with respect to the sidewall of the bodythat is different in magnitude with respect to the angle defined by eachother bottom surface of the plurality of arms. Additionally, in someembodiments, an angle may be defined between each arm of the pluralityof arms with respect to another adjacent arm of the plurality of armswhen viewed in the top plan view. Each of such angles may be differentin magnitude from each other. Additionally, each foot of the pluralityof feet may be spaced apart from the body, when viewed in the top planview, a distance different in magnitude with respect to the distancedefined by each other foot of the plurality of feet.

In some embodiments, each arm of the plurality of arms may be coupled tothe body via a joint such that each arm is movable relative to the body.Additionally or alternatively, each foot of the plurality of feet may becoupled to the corresponding arm via a joint such that each foot ismovable relative to the corresponding arm. In some embodiments, theplurality of arms may comprise at least three arms extending from thebody. Additionally, in some embodiments, each foot of the plurality offeet may include a longitudinal passageway defined therein, each of thelongitudinal passageways of the plurality of feet being sized to receivea bone guide pin.

According to another aspect, a customized patient-specific orthopaedicinstrument for facilitating implantation of an acetabular cup prosthesisin a coxal bone of a patient may include a customized patient-specificacetabular reaming guide. The customized patient-specific acetabularreaming guide may include a body having a longitudinal passagewaydefined therethrough, a plurality of arms coupled to the body viacorresponding joints such that each arm of the plurality of arms isseparately movable with respect to the body and a plurality of feetconfigured to contact a coxal bone of a patient. Each foot of theplurality of feet may be coupled to a corresponding arm of the pluralityof arms via a corresponding joint such that each foot of the pluralityof feet is separately movable with respect to the body. Additionallyeach foot of the plurality of feet may include a bottom, bone-facingsurface having a customized patient-specific negative contour configuredto receive a portion of the patient's coxal bone having a correspondingpositive contour. In some embodiments, each foot of the plurality offeet may include a longitudinal passageway defined therein, each of thelongitudinal passageways of the plurality of feet being sized to receivea bone guide pin.

According to a further aspect, a method for performing an orthopaedicbone reaming procedure on a patient's acetabulum to facilitateimplantation of an acetabular cup prosthesis in a coxal bone of thepatient may include positioning a customized patient-specific acetabularreaming guide on the patient's coxal bone. The customizedpatient-specific acetabular reaming guide may include a body having alongitudinal passageway defined therethrough and a plurality of feetcoupled to the body and configured to contact the coxal bone of thepatient. Each foot of the plurality of feet may be positioned relativeto the body based on a predetermined degree of version and inclinationangles of the acetabular cup prosthesis when implanted in the patient'scoxal bone.

The method may also include drilling a pilot hole into the patient'sacetabulum using the longitudinal passageway of the body as a drillguide. Additionally, the method may include inserting a bone guide pininto the pilot hole formed in the patient's acetabulum. The method mayfurther include advancing a cannulated acetabular reamer over the guidepin. The method may also include reaming the patient's acetabulum withthe cannulated acetabular reamer using the bone guide pin as a guide forthe cannulated reamer.

According to yet a further aspect, a method for performing anorthopaedic bone reaming procedure on a patient's acetabulum tofacilitate implantation of an acetabular cup prosthesis in a coxal boneof the patient may include positioning a customized patient-specificacetabular reaming guide on the patient's coxal bone. The customizedpatient-specific acetabular reaming guide may include a body having alongitudinal passageway defined therethrough and a plurality of feetconfigured to contact the coxal bone of the patient. Each foot of theplurality of feet may be coupled to the body and may have a longitudinalpassageway defined therethrough. Each foot of the plurality of feet maybe positioned relative to the body based on a predetermined degree ofversion and inclination angles of the acetabular cup prosthesis whenimplanted in the patient's coxal bone.

The method may include drilling a plurality of pilot holes into thepatient's coxal bone using the longitudinal passageways of the pluralityof feet as drill guides. The method may also include inserting a boneguide pin through each longitudinal passageway of the plurality of feetand into each of the corresponding pilot holes formed in the patient'scoxal bone. Additionally, the method may include securing an acetabularreamer within the longitudinal passageway of the body. The method mayfurther include reaming the patient's acetabulum with the acetabularreamer using the plurality of guide pins as guides for the acetabularreamer.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is a simplified flow diagram of a method for designing andfabricating a customized patient-specific acetabular orthopaedicsurgical instrument;

FIG. 2 is a perspective view of one embodiment of a customizedpatient-specific acetabular orthopaedic surgical instrument;

FIG. 3 is a side elevation view of the customized patient-specificacetabular orthopaedic surgical instrument of FIG. 2;

FIG. 4 is a top plan view of the customized patient-specific acetabularorthopaedic surgical instrument of FIG. 2;

FIG. 5 is a cross-sectional view of one embodiment of a mounting foot ofthe customized patient-specific acetabular orthopaedic surgicalinstrument of FIG. 2;

FIG. 6 is a perspective view of another embodiment of a customizedpatient-specific acetabular orthopaedic surgical instrument;

FIG. 7 is a side elevation view of the customized patient-specificacetabular orthopaedic surgical instrument of FIG. 6;

FIG. 8 is a top plan view of the customized patient-specific acetabularorthopaedic surgical instrument of FIG. 6;

FIG. 9 is a simplified flow diagram of a method of performing anacetabular orthopaedic surgical procedure;

FIG. 10 is a perspective view of one embodiment of a cannulated reamerfor use in the method of FIG. 9;

FIG. 11 is a side elevation view of an acetabular prosthesis positionedfor implantation using a guide pin secured to the patient's bone via useof the customized patient-specific acetabular orthopaedic surgicalinstrument of FIG. 2 or FIG. 6;

FIG. 12 is a perspective view of another embodiment of a customizedpatient-specific acetabular orthopaedic surgical instrument;

FIG. 13 is a side elevation view of the customized patient-specificacetabular orthopaedic surgical instrument of FIG. 12;

FIG. 14 is a top plan view of the customized patient-specific acetabularorthopaedic surgical instrument of FIG. 12;

FIG. 15 is a side elevation view of the customized patient-specificacetabular orthopaedic of FIG. 12 coupled to a cannulated reamer;

FIG. 16 is a perspective view of another embodiment of a customizedpatient-specific acetabular orthopaedic surgical instrument;

FIG. 17 is a side elevation view of the customized patient-specificacetabular orthopaedic surgical instrument of FIG. 16;

FIG. 18 is a top plan view of the customized patient-specific acetabularorthopaedic surgical instrument of FIG. 16;

FIG. 19 is a side elevation view of the customized patient-specificacetabular orthopaedic surgical instrument of FIG. 16 coupled to ancannulated reamer;

FIG. 20 is a simplified flow diagram of a method of performing anacetabular orthopaedic surgical procedure; and

FIG. 21 is a side elevation view of an acetabular prosthesis positionedfor implantation using the customized patient-specific acetabularorthopaedic surgical instrument of FIG. 12 or FIG. 16.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

Referring to FIG. 1, an algorithm 10 for fabricating a customizedpatient-specific orthopaedic surgical instrument is illustrated. What ismeant herein by the term “customized patient-specific orthopaedicsurgical instrument” is a surgical tool for use by a surgeon inperforming an orthopaedic surgical procedure that is intended, andconfigured, for use on a particular patient. As such, it should beappreciated that, as used herein, the term “customized patient-specificorthopaedic surgical instrument” is distinct from standard, non-patientspecific orthopaedic surgical instruments that are intended for use on avariety of different patients. Additionally, it should be appreciatedthat, as used herein, the term “customized patient-specific orthopaedicsurgical instrument” is distinct from orthopaedic prostheses, whetherpatient-specific or generic, which are surgically implanted in the bodyof the patient. Rather, customized patient-specific orthopaedic surgicalinstruments are used by an orthopaedic surgeon to assist in theimplantation of orthopaedic prostheses.

In some embodiments, the customized patient-specific acetabularorthopaedic surgical instrument may be customized to the particularpatient based on the location at which the instrument is to be coupledto one or more bones of the patient, such as in an area of the patient'scoxal bone proximate to the acetabulum. For example, in someembodiments, the customized patient-specific acetabular orthopaedicsurgical instrument may include one or more bone-contacting or facingsurfaces having a negative contour that matches the contour of a portionof the relevant bone of the patient, which is discussed in more detailbelow in regard to FIG. 5. As such, the customized patient-specificacetabular orthopaedic surgical instrument is configured to be coupledto the patient's coxal bone in a unique location and position withrespect to the patient's bony anatomy. That is, the negative contours ofthe bone-contacting surfaces are configured to receive a matchingcontour surface of the portion of the patient's coxal bone. As such, theorthopaedic surgeon's guesswork and/or intra-operative decision-makingwith respect to the placement of the patient-specific acetabularorthopaedic surgical instrument are reduced. For example, theorthopaedic surgeon may not be required to locate landmarks of thepatient's bone to facilitate the placement of the patient-specificacetabular orthopaedic surgical instrument, which typically requiressome amount of estimation on part of the surgeon. Rather, theorthopaedic surgeon may simply couple the customized patient-specificacetabular orthopaedic surgical instrument to the patient's coxal bonein the unique location. When so coupled, the patient-specific acetabularorthopaedic surgical instrument defines a particular degree of versionand inclination angles relative to the acetabulum and the intendedacetabular orthopaedic prosthesis.

As shown in FIG. 1, the method 10 includes process steps 12 and 14, inwhich an orthopaedic surgeon performs pre-operative planning of theacetabular orthopaedic surgical procedure to be performed on a patient.The process steps 12 and 14 may be performed in any order orcontemporaneously with each other. In process step 12, a number ofmedical images of the patient's acetabulum and the surrounding bonyanatomy are generated. To do so, the orthopaedic surgeon or otherhealthcare provider may operate an imaging system to generate themedical images. The medical images may be embodied as any number andtype of medical images capable of being used to generate athree-dimensional rendered model of the patient's acetabulum andsurrounding bony anatomy. For example, the medical images may beembodied as any number of computed tomography (CT) images, magneticresonance imaging (MRI) images, or other three-dimensional medicalimages. Additionally, or alternatively, as discussed in more detailbelow in regard to process step 18, the medical images may be embodiedas a number of X-ray images or other two-dimensional images from which athree-dimensional rendered model of the area of the patient's coxal boneproximate to the acetabulum and the surrounding bony anatomy may begenerated.

In process step 14, the orthopaedic surgeon may determine any additionalpre-operative constraint data. The constraint data may be based on theorthopaedic surgeon's preferences, preferences of the patient,anatomical aspects of the patient, guidelines established by thehealthcare facility, or the like. For example, the constraint data mayinclude the orthopaedic surgeon's preference for the amount ofinclination and version for the acetabular prosthesis, the amount of thebone to ream, the size range of the orthopaedic implant, and/or thelike. In some embodiments, the orthopaedic surgeon's preferences aresaved as a surgeon's profile, which may be used as a default constraintvalues for further surgical plans.

In process step 16, the medical images and the constraint data, if any,are transmitted or otherwise provided to an orthopaedic surgicalinstrument vendor or manufacturer. The medical images and the constraintdata may be transmitted to the vendor via electronic means such as anetwork or the like. After the vendor has received the medical imagesand the constraint data, the vendor processes the images in step 18. Theorthopaedic surgical instrument vendor or manufacturer process themedical images to facilitate the determination of the proper planes ofinclination and version, implant sizing, and fabrication of thecustomized patient-specific acetabular orthopaedic surgical instrumentas discussed in more detail below.

In process step 20, the vendor may convert or otherwise generatethree-dimensional images from the medical images. For example, inembodiments wherein the medical images are embodied as a number oftwo-dimensional images, the vendor may use a suitable computer algorithmto generate one or more three-dimensional images form the number oftwo-dimensional images. Additionally, in some embodiments, the medicalimages may be generated based on an established standard such as theDigital Imaging and Communications in Medicine (DICOM) standard. In suchembodiments, an edge-detection, thresholding, watershed, orshape-matching algorithm may be used to convert or reconstruct images toa format acceptable in a computer aided design application or otherimage processing application.

In process step 22, the vendor may process the medical images, and/orthe converted/reconstructed images from process step 20, to determine anumber of aspects related to the bony anatomy of the patient such as theanatomical axis of the patient's bones, the mechanical axis of thepatient's bone, other axes and various landmarks, and/or other aspectsof the patient's bony anatomy. To do so, the vendor may use any suitablealgorithm to process the images.

In process step 24, the desired inclination and version planes forimplantation of the acetabular orthopaedic prosthesis are determined.The planned inclination and version planes may be determined based onthe type, size, and position of the acetabular orthopaedic prosthesis tobe used during the orthopaedic surgical procedure; the process images,such as specific landmarks identified in the images; and the constraintdata supplied by the orthopaedic surgeon in process steps 14 and 16. Thetype and/or size of the acetabular orthopaedic prosthesis may bedetermined based on the patient's anatomy and the constraint data. Forexample, the constraint data may dictate the type, make, model, size, orother characteristic of the acetabular orthopaedic prosthesis. Theselection of the acetabular orthopaedic prosthesis may also be modifiedbased on the medical images such that an acetabular orthopaedicprosthesis that is usable with the acetabulum of the patient and thatmatches the constraint data or preferences of the orthopaedic surgeon isselected.

In addition to the type and size of the acetabular orthopaedicprosthesis, the planned location and position of the acetabularorthopaedic prosthesis relative to the patient's bony anatomy isdetermined. To do so, a digital template of the acetabular orthopaedicprosthesis may be overlaid onto one or more of the processed medicalimages. The vendor may use any suitable algorithm to determine arecommended location and orientation of the acetabular orthopaedicprosthesis (i.e., the digital template) with respect to the patient'sbone based on the processed medical images (e.g., landmarks of thepatient's acetabulum defined in the images) and/or the constraint data.Additionally, any one or more other aspects of the patient's bonyanatomy may be used to determine the proper positioning of the digitaltemplate.

In some embodiments, the digital template along with surgical alignmentparameters may be presented to the orthopaedic surgeon for approval. Theapproval document may include the implant's planned inclination andversion planes, the orientation of the transverse acetabular ligamentand labrum, and other relevant landmarks of the patient's bony anatomy.

The proper inclination and version planes for the acetabular orthopaedicprosthesis may then be determined based on the determined size,location, and orientation of the acetabular orthopaedic prosthesis. Inaddition, other aspects of the patient's bony anatomy, as determined inprocess step 22, may be used to determine or adjust the plannedinclination and version planes. For example, the determined mechanicalaxis, landmarks, and/or other determined aspects of the relevant bonesof the patient may be used to determine the planned inclination andversion planes.

In process step 26, a model of the customized patient-specificacetabular orthopaedic surgical instrument is generated. In someembodiments, the model is embodied as a three-dimensional rendering ofthe customized patient-specific acetabular orthopaedic surgicalinstrument. In other embodiments, the model may be embodied as a mock-upor fast prototype of the customized patient-specific acetabularorthopaedic surgical instrument. The patient-specific acetabularorthopaedic surgical instrument to be modeled and fabricated may bedetermined based on the acetabular orthopaedic surgical procedure to beperformed, the constraint data, and/or the type of orthopaedicprosthesis to be implanted in the patient.

The particular shape of the customized patient-specific acetabularorthopaedic surgical instrument is determined based on the plannedlocation and implantation angles of the acetabular orthopaedicprosthesis relative to the patient's acetabulum. The planned location ofthe customized patient-specific acetabular orthopaedic surgicalinstrument relative to the patient's acetabulum may be selected basedon, in part, the planned inclination and version planes of the patient'sacetabulum as determined in step 24. For example, in some embodiments,the customized patient-specific acetabular orthopaedic surgicalinstrument is embodied as an acetabular reamer guide. In suchembodiments, the location of the acetabular reamer guide is selectedsuch that the acetabular reamer guide is usable to position theacetabular orthopaedic prosthesis at the planned inclination and versionplanes determined in process step 24. Additionally, the planned locationof the orthopaedic surgical instrument may be based on the identifiedlandmarks of the patient's acetabulum identified in process step 22.

In some embodiments, the particular shape or configuration of thecustomized patient-specific acetabular orthopaedic surgical instrumentmay be determined based on the planned location of the instrumentrelative to the patient's bony anatomy. That is, the customizedpatient-specific acetabular orthopaedic surgical instrument may includea bone-contacting surface having a negative contour that matches thecorresponding contour of a portion of the bony anatomy of the patientsuch that the orthopaedic surgical instrument may be coupled to the bonyanatomy of the patient in a unique location, which corresponds to thepre-planned location for the instrument. When the orthopaedic surgicalinstrument is coupled to the patient's bony anatomy in the uniquelocation, one or more guides (e.g., cutting or drilling guide) of theorthopaedic surgical instrument may be aligned to the inclination andversion planes, as discussed above.

After the model of the customized patient-specific acetabularorthopaedic surgical instrument has been generated in process step 26,the model is validated in process step 28. The model may be validatedby, for example, analyzing the rendered model while coupled to thethree-dimensional model of the patient's anatomy to verify thecorrelation of reaming guides, inclination and version planes, and/orthe like. Additionally, the model may be validated by transmitting orotherwise providing the model generated in step 26 to the orthopaedicsurgeon for review. For example, in embodiments wherein the model is athree-dimensional rendered model, the model along with thethree-dimensional images of the patient's acetabulum and area of thecoxal bone proximate to the acetabulum may be transmitted to the surgeonfor review. In embodiments wherein the model is a physical prototype,the model may be shipped to the orthopaedic surgeon for validation.

After the model has been validated in process step 28, the customizedpatient-specific acetabular orthopaedic surgical instrument isfabricated in process step 30. The customized patient-specificacetabular orthopaedic surgical instrument may be fabricated using anysuitable fabrication device and method. Additionally, the customizedpatient-specific acetabular orthopaedic instrument may be formed fromany suitable material such as a metallic material, a plastic material,or combination thereof depending on, for example, the intended use ofthe instrument. The fabricated customized patient-specific acetabularorthopaedic instrument is subsequently shipped or otherwise provided tothe orthopaedic surgeon. The surgeon performs the orthopaedic surgicalprocedure in process step 32 using the customized patient-specificacetabular orthopaedic surgical instrument. As discussed above, becausethe orthopaedic surgeon does not need to determine the proper locationof the orthopaedic surgical instrument intra-operatively, whichtypically requires some amount of estimation on part of the surgeon, theguesswork and/or intra-operative decision-making on part of theorthopaedic surgeon is reduced.

It should also be appreciated that variations in the bony of anatomy ofthe patient may require more than one customized patient-specificacetabular orthopaedic surgical instrument to be fabricated according tothe method described herein. For example, the patient may require theimplantation of two acetabular orthopaedic prostheses to replace bothnatural hips. As such, the surgeon may follow the method 10 of FIG. 1 tofabricate a different customized patient-specific acetabular orthopaedicsurgical instrument for use in replacing each natural hip. Eachcustomized patient-specific acetabular orthopaedic surgical instrumentdefines a particular degree of version and inclination angles relativeto each particular acetabulum that is different due to the variation inthe bony anatomy of each hip.

Referring now to FIGS. 2-4, in one embodiment, the customizedpatient-specific acetabular orthopaedic surgical instrument may beembodied as an acetabular reamer guide 50. The acetabular reamer guide50 is usable by a surgeon to secure a bone guide pin to the patient'sacetabulum in a predetermined location and orientation that willposition the acetabular orthopaedic prosthesis at the desired,predetermined angles of inclination and version. The bone guide pin issubsequently used to orient and guide a cannulated reamer as discussedin more detail below.

The illustrative acetabular reamer guide 50 includes a drill guide 52and a plurality of mounting feet 54. Each of the mounting feet 54 iscoupled to the drill guide 52 via a corresponding arm 56. In theillustrative embodiment of FIGS. 2-4, the arms 56, mounting feet 54, anddrill guide 52 are each formed from separate pieces. For example, thearms 56 may be secured to the mounting feet 54 and/or the drill guide 52via suitable fasteners such as screws, bolts, adhesive, or the like. Itshould be appreciated that in other embodiments the drill guide 52,mounting feet 54, and arms 56 could be formed as a monolithic component.The drill guide 52, mounting feet 54, and arms 56 may be formed from anysuitable material such as a resilient plastic or metallic material. Inone particular embodiment, the acetabular reamer guide 50 is formed froman implant-grade metallic material such as titanium or cobalt chromium.

The drill guide 52 includes a body 58 having a drill guide longitudinalpassageway 60 defined therethrough and a bottom surface 62. In theillustrative embodiment of FIG. 2, the body 58 has a substantiallycylindrical shape but may have other shapes in other embodiments. Forexample, in some embodiments, the body 58 may have a substantiallyrectangular, triangular, or polygonal cross-section. The longitudinalpassageway 60 is sized such that a bone guide pin is insertable throughthe passageway 60 to allow the guide pin to be secured to the patient'sacetabulum. For example, the passageway 60 may have an inner diameter 64(see FIG. 3) that is slightly larger than the outer diameter of theguide pin. Additionally, the passageway 60 may have any cross-sectionalshape suitable for receiving a drill bit of a bone drill and guide pintherethrough. For example, in FIGS. 2-4 the passageway 60 has asubstantially circular cross-section, but in other embodiments, the body58 may include a passageway 60 configured to receive a guide pin with adifferent cross-sectional shape.

Each of the mounting feet 54 is configured to contact the patient's bonyanatomy during use. In the illustrative embodiment of FIGS. 2-4, each ofthe mounting feet 54 is substantially cylindrical in shape but may haveother shapes in other embodiments. For example, in some embodiments, themounting feet 54 may have a substantially rectangular, triangular, orpolygonal cross-section. Each of the mounting feet 54 includes a bottomsurface 66, which is configured to contact a portion of the area of thepatient's coxal bone proximate to the acetabulum. Each mounting foot 54also includes a top surface 68 opposite the bottom surface 66 and asidewall 70. As discussed in greater detail below, the position of eachmounting foot 54 relative to the drill guide 52 and relative to eachother allows the acetabular reamer guide 50 to be coupled to thepatient's coxal bone in a substantially unique orientation and locationbased on the contour of the patient's coxal bone. Additionally, in someembodiments, the bottom surface 66 of each mounting foot 54 may becustomized to the contour of the patient's acetabulum. For example, asillustrated in FIG. 5, the bottom surfaces 66 of the mounting feet 54are configured with a customized patient-specific negative contour 72configured to receive a portion of the corresponding contour of thepatient's coxal bone proximate to the acetabulum. As such, theacetabular reamer guide 50 is configured to be coupled to the patient'scoxal bone in a desired position and orientation, which has beenpredetermined to establish the desired inclination and version planes ofthe acetabular orthopaedic prosthesis.

Each of the mounting feet 54 has a longitudinal length 74, which may bedetermined based on the surface contour of the patient's bony anatomysuch that the acetabular reamer guide 50 is positioned at the desiredangles of inclination and version. For example, in the illustrativeembodiment of FIG. 3, the length 74 of each mounting foot 54 is equal toone another. In other embodiments, the length 74 may be differentrelative to each mounting foot 54 to position the reamer guide 50 at thedesired angles of inclination and version.

In some embodiments, as illustrated in FIG. 3, the bottom surface 62 ofthe drill guide 52 may be offset a distance 76 from the top surface 68of each mounting foot 54. That is, the bottom surface 62 may benon-coplanar with the top surface 68 of one or more of the mounting feet54. In the illustrative embodiment of FIG. 3, the distance 76 for eachmounting foot 54 is equal. In other embodiments, the distance 76 may bedifferent such that the acetabular reamer guide 50 is positioned in theplanned orientation and location, which has been predetermined toestablish the desired inclination and version planes of the acetabularorthopaedic prosthesis. Additionally, in other embodiments, the bottomsurface 62 of the drill guide 52 may be coplanar with the top surface 68of each mounting foot 54 such that the distance 76 is equal to zero.Further, in some embodiments, the drill guide 52 may extend downwardlysuch that the bottom surface 62 of the drill guide 52 is substantiallyequal to, higher than, or lower than the bottom surfaces 66 of themounting feet 54. For example, in some embodiments, the bottom surface62 of the drill guide 52 may be positioned medially relative to themounting feet 54 when the acetabular reaming guide 50 is coupled to thepatient's coxal bone.

As discussed above, the arms 56 secure the mounting feet 54 to the drillguide 52. In the illustrative embodiment, the arms 56 are embodied asrectangular shafts, but may have other shapes and configurations inother embodiments. For example, the arms 56 may be straight, curved orbowed, angled, or the like in other embodiments. When viewed from theside elevation perspective of FIG. 3, an angle 78 is defined between abottom surface of each arm 56 and the bottom surface 62 of drill guide52. In the illustrative embodiment, each angle 78 is equal to oneanother. In other embodiments, each angle 78 may be different dependingon the patient's anatomy and the desired angles of inclination andversion of the acetabular orthopaedic prosthesis. Additionally, whenviewed from the top plan of FIG. 4, each arm 56 extends a distance 86from the drill guide 52. It should be appreciated that in theillustrative embodiment of FIG. 4, the arms 56 extend the same distance86 from the drill guide 52. However, in other embodiments, the arms 56may each extend a distance 86 that is different from one anotherdepending on the patient's anatomy and the desired angles of inclinationand version of the acetabular orthopaedic prosthesis.

Further, when viewed from the top plan view of FIG. 4, the arms 56extend from drill guide 52 in a configuration so as to define a numberof different angles 80, 82, and 84. For example, as illustrated in FIG.4, an arm 90 and an arm 92 define an angle 80 therebetween, an arm 90and an arm 94 define an angle 82 therebetween, and the arm 92 and thearm 94 define an angle 84 therebetween. In some embodiments, as shown inFIG. 4, the magnitude of angle 84 is greater than the magnitude of angle82, which is greater than the magnitude of angle 80. Like many otherdimensional characteristics described herein, the magnitude of theangles 80, 82, and 84 may be customized to any degree required for theparticular patient. In some embodiments, the arms 56 may extend from thedrill guide 52 in a substantially uniform configuration such that theangle defined between each arm is substantially equal.

Referring now to FIGS. 6-8, in another embodiment, the acetabular reamerguide 50 is adjustable by the surgeon pre-operatively orinteroperatively. Some features of the embodiment illustrated in FIGS.6-8 are substantially similar to those discussed above in reference tothe embodiment of FIGS. 2-4. Those features that are substantiallysimilar have the same reference numbers as designated in the embodimentof FIGS. 2-4.

In the illustrative embodiment of FIGS. 6-8, each arm 56 is moveablycoupled to the drill guide 52 and each mounting foot 54. In particular,each arm 56 is secured to a joint 120 of drill guide 52 and acorresponding joint 122 of each mounting foot 54. The joints 120, 122may be embodied as hinges, universal joints, or the like configured toallow positioning of the mounting feet 54 relative to the drill guide52. The joints 120, 122 may include a locking mechanism (not shown)capable of fixing each arm 56 at a desired position. It will beappreciated that in other embodiments not all arms 56 may be moveablysecured to the drill guide 52 and/or mounting feet 54. Additionally, theacetabular reamer guide 50 may include any combination of joints toposition the acetabular reamer guide 50 at the planned orientation andlocation to establish the desired inclination and version planes of theacetabular orthopaedic prosthesis.

It should be appreciated that the acetabular reamer guide 50 isadjustable by the orthopaedic surgeon to improve the coupling of theguide 50 to the patient's bony anatomy. For example, when viewed fromthe side elevation perspective of FIG. 7, each angle 78 defined betweenthe bottom surface 62 of the drill guide 52 and each arm 56 isadjustable to position the acetabular reamer guide 50 at the plannedorientation and location. Additionally, an angle 124 is defined betweeneach arm 56 and the sidewall 70 of each mounting foot 54. In theillustrative embodiment of FIG. 7, the angle 124 is adjustable toposition the acetabular reamer guide 50 at the desired location andorientation. In other embodiments, each angle 124 may or may not beadjustable depending on the patient's bony anatomy.

When viewed from the top plan of FIG. 8, the angles 80, 82, and 84defined between the arms 56 are also adjustable. The angles 80, 82, and84 may be increased or decreased depending on the patient's bony anatomyto position the acetabular reamer guide 50 at the desired location andorientation. For example, any two of the arms 56 may be moved toward oraway from each other. In other embodiments, the angles 80, 82, and 84may or may not be adjustable depending on the patient's bony anatomy.

Referring to FIG. 9, an orthopaedic surgical procedure 100 using theacetabular reamer guide 50 is illustrated. The surgeon may perform theprocedure 100 in process step 32 of method 10, which is illustrated inFIG. 1 and described above. In process step 102, the surgeon positionsthe acetabular reamer guide 50 on the patient's coxal bone. Because theacetabular reamer guide 50 is customized to the particular patient, theguide 50 is coupled to the patient's coxal bone in a substantiallyunique, predetermined location and orientation. For example, in thoseembodiments wherein the bottom surfaces 66 of the mounting feet 54include a customized patient-specific contour, the acetabular reamerguide 50 is positioned on the patient's coxal bone such that acorresponding contour of the surface of the patient's coxal bone isreceived in the negative contour of the bottom surfaces 66 of themounting feet 54. Additionally, in some embodiments, the surgeon mayadjust the position of the acetabular reamer guide 50 pre-operatively orinteroperatively. For example, in those embodiments wherein the each arm56 is moveably secured to the drill guide 52 and each mounting foot 54,the surgeon may adjust the position of the acetabular reamer guide 50 toimprove the coupling of the guide 50 to the patient's bony anatomy. Oncepositioned, the acetabular reamer guide 50 defines the desiredinclination and version angles relative to the patient's acetabulumintended for the acetabular orthopaedic prosthesis.

In process step 104, the surgeon inserts a drill bit of an orthopaedicdrill through the passageway 60 of the drill guide 52 of the acetabularreamer guide 50. The surgeon drills a pilot hole in the patient'sacetabulum using the drill guide 52. It should be appreciated that thepilot hole is oriented to position the acetabular orthopaedic prosthesisat the desired inclination and version angles. Thereafter, the surgeonmay remove the drill bit from the passageway 60.

In process step 106, the surgeon inserts a guide pin (see FIG. 10)through the passageway 60 of the drill guide 52 and into the pilot holedefined in the patient's acetabulum. The guide pin is then screwed orotherwise secured in the patient's acetabulum. After securing the guidepin to the patient's acetabulum, the surgeon removes the acetabularreamer guide 50, leaving the guide pin secured to the patient'sacetabulum. Alternatively, in some embodiments, the surgeon may removethe acetabular reamer guide 50 after establishing the pilot hole in thepatient's acetabulum. The surgeon may subsequently secure the guide pinin the pilot hole without the use of the drill guide 52.

In process step 108, the surgeon advances a cannulated reamer (see FIG.10) over the guide pin. As shown in FIG. 10, the cannulated reamer 126includes a centrally-defined cannula or passageway 128 sized to receivea guide pin 130. The surgeon may advance the cannulated reamer 126 overthe guide pin 130 to begin reaming the patient's acetabulum. It shouldbe appreciated that because the guide pin 130 was secured to thepatient's acetabulum in a predetermined location and orientation basedon the desired version and inclination angle of the acetabularprosthesis, the reaming of the patient's acetabulum is guided so as tosize the patient's acetabulum to receive the acetabular prosthesisaccording to the desired version and inclination angles.

In some embodiments, the guide pin 130 may also be used as a guideduring the implantation of an acetabular prosthesis. That is, asillustrated in FIG. 11, after the surgeon has reamed the patient's boneusing the cannulated reamer 126, the surgeon may position an acetabularprosthesis 140, which may include an acetabular cup 142 and a bearingliner 144 received within the acetabular cup 142, over the guide pin130. The acetabular prosthesis 140 includes an aperture 146, which maybe threaded or non-threaded, positioned at the dwell point of theacetabular cup 142. The acetabular prosthesis 140 is positioned suchthat the guide pin 130 is received through the aperture 146. Theacetabular prosthesis 140 may subsequently be slid down the guide pin130 to the surgically-prepared acetabulum of the patient.

The acetabular prosthesis 140 may be implanted via use of an impactor orinserter 148. In the illustrative embodiment, the impactor 148 issubstantially cylindrical in shape and has an outer diametersubstantially equal to the outer diameter of the acetabular prosthesis140. The impactor 148 is includes a centrally-positioned passageway 149,which is sized to receive the end of the guide pin 130 such that theimpactor 148 may be positioned over the acetabular prosthesis 140. Whenso positioned, the impactor 148 contacts the rim of the acetabularprosthesis 140. The surgeon may then impact the impactor 148 (e.g., viause of a surgical hammer) to cause the acetabular prosthesis 140 to seedinto the patient's surgically-prepared acetabulum. Of course, in otherembodiments, other devices and tools may be used to implant theacetabular prosthesis 140 using the guide pin 130 as a guide. Forexample, in some embodiment, the impactor may be embodied as, orotherwise include, a stem configured to be received in the aperture 146.In such embodiments, the stem and aperture 146 are threaded. Inaddition, the stem is cannulated and configured to receive the guide pin130 therein. In should be appreciated that in such embodiments, theaperture 146 has a greater diameter than the guide pin 130 to allow thestem of the impactor to be received therein. Regardless, once theacetabular prosthesis 140 is implanted, the guide pin 130 may beremoved. It should be appreciated that because the acetabular prosthesis140 is implanted using the guide pin 130 as a guide, the acetabularprosthesis 140 is implanted substantially at the predetermined locationand orientation (e.g., at the predetermined inclination and versionangles).

Although the acetabular reamer guide 50 has been described above inregard to a customized patient-specific instrument, it should beappreciated that the acetabular reamer guide 50 may not be customized toa specific patient in other embodiments. That is, in some embodiment theacetabular reamer guide 50 may be configured to use on a variety ofpatients. For example, the acetabular reamer guide 50 illustrated inFIG. 7 may be embodied as a non-patient-specific orthopaedic instrument.In such embodiments, the acetabular reamer guide 50 may bepre-operatively and/or intra-operatively adjusted by the surgeon toprovide the desired inclination and version angles for the acetabularprosthesis. As such, it should be appreciated that because theacetabular reamer guide 50 is adjustable in such embodiments, the guide50 may be used by the surgeon on a variety of patients and adjustedintra-operatively as desired by the orthopaedic surgeon.

Referring now to FIGS. 12-15, in another embodiment, the customizedpatient-specific acetabular orthopaedic surgical instrument may beembodied as an acetabular reamer guide 150. The acetabular reamer guide150 is usable by a surgeon to secure multiple guide pins to the area ofthe patient's coxal bone proximate to the acetabulum in a predeterminedlocation and orientation. The guide pins are subsequently used to orientand guide a cannulated reamer secured to the acetabular reamer guide 150as discussed in more detail below.

The illustrative acetabular reamer guide 150 includes a reamer mount 152and a plurality of mounting feet 154. Each of the mounting feet 154 issecured to the reamer mount 152 via a corresponding arm 156. In theillustrative embodiment of FIGS. 12-15, the arms 156, mounting feet 154,and reamer mount 152 are formed as a monolithic component from materialssimilar to those disclosed in regard to the embodiment of FIGS. 2-4. Inother embodiments, the arms 156, mounting feet 154, and reamer mount 152each may be formed as separate pieces and secured together by meanssimilar to those disclosed in regard to the embodiment of FIGS. 2-4.

In the illustrative embodiment, the reamer mount 152 includes a body 158having a reamer passageway 160 defined therethrough and a bottom surface162. The illustrative body 158 has a substantially cylindrical shape butmay have other shapes in other embodiments. The passageway 160 is sizedsuch that a bone reamer 218 is insertable through the passageway 160 tosecure the reamer 218 to the reamer mount 152, which is discussed inmore detail below in regard to FIG. 15. For example, the passageway 60may have an inner diameter 64 (see FIG. 13) that is slightly larger thanthe outer diameter of the body 222 of the reamer 218. Additionally, thepassageway 160 may have any cross-sectional shape suitable for receivinga cannulated reamer therethrough. For example, in FIGS. 12-15 thepassageway 160 has a substantially circular cross-section, but in otherembodiments, the body 158 may include a passageway 160 configured toreceive a reamer 218 with a different cross-sectional shape.

Each of the mounting feet 154 is configured to contact the patient'sbony anatomy during use. In the illustrative embodiment of FIGS. 12-15,each of the mounting feet 154 is substantially cylindrical in shape butmay have other shapes in other embodiments, similar to those disclosedin regard to the embodiment of FIGS. 2-4. Each of the mounting feet 154includes a bottom surface 166, which is configured to contact a portionof the patient's coxal bone proximate to the acetabulum. The mountingfoot 154 also includes a top surface 168 opposite the bottom surface 166and a sidewall 170. As discussed in greater detail below, the positionof each mounting foot 154 relative to the reamer mount 152 and relativeto each other allows the acetabular reamer guide 150 to be coupled tothe patient's coxal bone in a substantially unique orientation andposition. Additionally, in some embodiments, the bottom surface 166 ofeach mounting foot 154 may be customized to the contour of the patient'sacetabulum. For example, similar to the embodiment illustrated in FIG.5, the bottom surfaces 166 of the mounting feet 154 may be configuredwith a customized patient-specific negative contour configured toreceive a portion of the corresponding contour of the patient's coxalbone proximate to the acetabulum. As such, the acetabular reamer guide150 is configured to be coupled to the patient's coxal bone in a plannedorientation and location, which has been predetermined to establish thedesired inclination and version planes of the acetabular orthopaedicprosthesis.

Each mounting foot 154 includes drill guide passageway 214 definedtherethrough. In the illustrative embodiment of FIG. 12, the passageways214 are sized such that a guide pin is insertable through eachpassageway 214 to allow the guide pin to be secured to the patient'scoxal bone proximate to the acetabulum. For example, the passageway 214may have an inner diameter 216 that is slightly larger than the outerdiameter of the guide pin. Additionally, the passageway 214 may have anycross-sectional shape suitable for receiving a drill bit of a bone drilland guide pin therethrough. For example, in FIGS. 12-15, the passageway214 of each mounting foot 154 has a substantially circularcross-section, but in other embodiments, each mounting foot 154 mayinclude a passageway 214 configured to receive a guide pin with adifferent cross-sectional shape.

Each of the mounting feet 154 has a length 174, which is based on thesurface contour of the patient's bony anatomy such that the acetabularreamer guide 150 is positioned at the desired angles of inclination andversion. For example, in the illustrative embodiment of FIG. 13, thelength 174 of each mounting foot 154 is equal to one another. In otherembodiments, the length 174 may be different relative to each mountingfoot 154 to position the reamer guide 150 at the desired angles ofinclination and version.

In some embodiments, as illustrated in FIG. 13, the bottom surface 162of the reamer mount 152 may be offset a distance 176 from the topsurface 168 of each mounting foot 154. In the illustrative embodiment ofFIG. 12, the distance 176 for each mounting foot 154 is equal. In otherembodiments, the distance 176 may be different such that the acetabularreamer guide 150 is positioned in the desired location and orientation,which has been predetermined to establish the desired inclination andversion planes of the acetabular orthopaedic prosthesis. Additionally,in other embodiments, the bottom surface 162 of the reamer mount 152 maybe coplanar with the top surface 168 of each mounting foot 154 such thatthe distance 176 is equal to zero. Further, in some embodiments, thereamer mount 152 may extend downwardly such that the bottom surface 162of the reamer mount 152 is substantially equal to, higher than, or lowerthan the bottom surfaces 166 of the mounting feet 154.

As discussed above, the arms 156 secure the mounting feet 154 to thereamer mount 152. In the illustrative embodiment, the arms 156 areembodied as rectangular shafts, but may have other shapes andconfigurations in other embodiments, similar to those disclosed inregard to the embodiment of FIGS. 2-4. When viewed from the sideelevation perspective of FIG. 13, an angle 178 is defined between eacharm 156 and the bottom surface 162 of reamer mount 152. In theillustrative embodiment, each angle 178 is equal to one another. Inother embodiments, each angle 178 may be different depending on thepatient's anatomy and the desired angles of inclination and version ofthe acetabular orthopaedic prosthesis. Additionally, when viewed fromthe top plan of FIG. 14, each arm 156 extends a distance 186 from thereamer mount 152. It should be appreciated that in the illustrativeembodiment of FIG. 14, the arms 156 extend the same distance 186 fromthe reamer mount 152. However, in other embodiments, each arm 156 mayextend a distance 186 that is different from one another depending onthe patient's anatomy and the desired angles of inclination and versionof the acetabular orthopaedic prosthesis.

Further, when viewed from the top plan of FIG. 14, the arms 156 extendfrom reamer mount 152 in a configuration so as to define a number ofdifferent angles 180, 182, and 184. For example, as illustrated in FIG.14, an arm 190 and an arm 192 define an angle 180 therebetween, an arm190 and an arm 194 define an angle 182 therebetween, and the arm 192 andthe arm 194 define an angle 184 therebetween. In some embodiments, asshown in FIG. 14, the arms 156 extend from the reamer mount 152 in asubstantially uniform configuration such that the angles 180, 182, and184 are of substantially equal magnitude. Like many other dimensionalcharacteristics described herein, the magnitude of the angles 180, 182,and 184 may be customized to any degree required for the particularpatient. For example, in some embodiments, the magnitude of angle 184may be greater than the magnitude of angle 182, which may be greaterthan the magnitude of angle 180.

As illustrated in FIG. 15, the body 158 of the reamer mount 152 issecured to the reamer 218 such that the reamer 218 is oriented at thedesired angles of inclination and version while reaming the patient'sacetabulum. In the embodiment illustrated in FIG. 15, the reamer 218 issecured to the body 158 of the reamer mount 152 via a screw 220. Itshould be appreciated that the reamer 218 may be secured to the body 158via other suitable fasteners such as bolts, adhesives, snapping tabs, orthe like. Additionally, in other embodiments, the reamer 218 may or maynot be secured to the body 158 of the reamer mount 152.

Referring now to FIGS. 16-19, in another embodiment, the acetabularreamer guide 150 is adjustable by the surgeon pre-operatively orinteroperatively. Some features of the illustrative embodiment of FIGS.16-19 are substantially similar to those discussed above in reference tothe embodiment of FIGS. 12-15. Those features that are substantiallysimilar have the same reference numbers as designated in the embodimentof FIGS. 12-15.

In the illustrative embodiment of FIGS. 16-19, each arm 156 is pivotallysecured to the reamer mount 152 and each mounting foot 154. Inparticular, each arm 156 is secured to a joint 230 of reamer mount 152and a corresponding joint 232 of each mounting foot 154. The joints 230,232 may be embodied as hinges, universal joints, or the like configuredto allow positioning of the mounting feet 154 relative to the drillguide 152. The joints 230, 232 may include a locking mechanism (notshown) capable of fixing each arm 156 at a desired position. It will beappreciated that in other embodiments not all arms 156 may be movablysecured to the reamer mount 152 and/or mounting feet 154. Additionally,the acetabular reamer guide 150 may include any combination of joints toposition the acetabular reamer guide 150 at the desired location andorientation to establish the desired inclination and version planes ofthe acetabular orthopaedic prosthesis.

It should be appreciated that the acetabular reamer guide 150 isadjustable by the orthopaedic surgeon to improve the coupling of theguide 150 to the patient's bony anatomy. For example, when viewed fromthe side elevation perspective of FIG. 17, each angle 178 definedbetween the bottom surface 162 of the reamer mount 152 and each arm 156is adjustable to position the acetabular reamer guide 150 at the desiredlocation and orientation. Additionally, an angle 234 is defined betweeneach arm 156 and the sidewall 170 of each mounting foot 154. In theillustrative embodiment of FIG. 17, the angle 234 is adjustable toposition the acetabular reamer guide 150 at the desired location andorientation. In other embodiments, each angle 234 may or may not beadjustable depending on the patient's bony anatomy.

When viewed from the top plan of FIG. 18, each angle 180, 182, and 184defined between the arms 156 is also adjustable. The angles 180, 182,and 184 may be increased or decreased depending on the patient's bonyanatomy to position the acetabular reamer guide 150 at the desiredlocation and orientation. For example, any two of the arms 156 may bemoved toward or away from each other. In other embodiments, the angles180, 182, and 184 may or may not be adjustable depending on thepatient's bony anatomy.

Referring to FIG. 20, an orthopaedic surgical procedure 200 using theacetabular reamer guide 150 is illustrated. The surgeon may perform theprocedure 200 in process step 32 of method 10, which is illustrated inFIG. 1 and described above. In process step 202, the surgeon positionsthe acetabular reamer guide 150 on the patient's coxal bone. Because theacetabular reamer guide 50 is customized to the particular patient, theguide 150 is coupled to the patient's coxal bone in a substantiallyunique, predetermined location and orientation. For example, in thoseembodiments wherein the bottom surfaces 166 of the mounting feet 154include a customized patient-specific contour, the acetabular reamerguide 150 is positioned on the patient's coxal bone such that acorresponding contour of the surface of the patient's coxal bone isreceived in the negative contour of the bottom surfaces 166 of themounting feet 154. Additionally, in some embodiments, the surgeon mayadjust the position of the acetabular reamer guide 150 pre-operativelyor interoperatively. For example, in those embodiments wherein the eacharm 156 is moveably secured to the reamer mount 152 and each mountingfoot 154, the surgeon may adjust the position of the acetabular reamerguide 150 to improve the coupling of the guide 150 to the patient's bonyanatomy. Once positioned, the acetabular reamer guide 150 defines thedesired inclination and version angles relative to the patient'sacetabulum intended for the acetabular orthopaedic prosthesis.

In process step 204, the surgeon inserts a drill bit of an orthopaedicdrill through the passageway 214 of the first mounting foot 154 of theacetabular reamer guide 150. The surgeon drills a first pilot hole inthe patient's coxal bone proximate to the acetabulum using thepassageway 214 of the first mounting foot 154 as drilling guide.Thereafter, the surgeon may remove the drill bit from the passageway 214of the first mounting foot 154. The surgeon repeats the process to drilla second and a third pilot hole in the patient's coxal bone proximate tothe acetabulum using the passageway 214 of a second and third mountingfoot 154. It should be appreciated that the first, second, and thirdpilot holes are oriented to position the acetabular orthopaedicprosthesis at the desired inclination and version angles.

In process step 206, the surgeon inserts a guide pin (see FIG. 15 orFIG. 19) through each passageway 214 of the mounting feet 154 and intothe pilot hole defined in the patient's coxal bone proximate to theacetabulum. The guide pins are then screwed or otherwise secured in thepatient's coxal bone. After securing the guide pins to the patient'sacetabulum, the surgeon removes the acetabular reamer guide 150, leavingthe guide pins secured to the patient's acetabulum. Alternatively, insome embodiments, the surgeon may remove the acetabular reamer guide 150after establishing the pilot holes in the patient's acetabulum. Thesurgeon may subsequently secure the guide pins in the pilot holeswithout the use of the mounting feet 54.

In process step 208, the surgeon secures the bone reamer 218 to theacetabular reamer guide 150. The surgeon then advances the acetabularreamer guide 150 (see FIG. 15 or FIG. 19) over the guide pins toposition the reamer 218 for reaming the patient's acetabulum. It shouldbe appreciated that because the guide pins 215 were secured to thepatient's acetabulum in a predetermined location and orientation basedon the desired version and inclination angle of the acetabularprosthesis, the reaming of the patient's acetabulum is guided so as tosize the patient's acetabulum to receive the acetabular prosthesisaccording to the desired version and inclination angles.

In some embodiments, the guide pins 215 may also be used as guidesduring the implantation of an acetabular prosthesis. That is, asillustrated in FIG. 21, after the surgeon has reamed the patient's boneusing the bone reamer 218, the surgeon may secure an acetabularprosthesis 240, which may include an acetabular cup 242 and a bearingliner 244 received within the acetabular cup 242, to the acetabularreamer guide 150 via use of an impactor or inserter 248. The impactor248 includes a housing or base 250 and a shaft 252 extending downwardlytherefrom. The shaft 252 includes a threaded end 254, which is receivedin a threaded aperture 246 of the acetabular cup 242. The housing 250 ofthe impactor 248 is sized to be received in the reamer passageway 160defined in the reamer mount 152 and secured to the mount 152 in a mannersimilar to the reamer 218 described in detail above.

Once the acetabular prosthesis 240 and impactor 248 have been secured tothe acetabular reamer guide 150, the guide 150 is again slid over theguide pins 215, which provide a guide during implantation of theacetabular prosthesis. The acetabular reamer guide 150 may subsequentlybe slid down the guide pins 215 to the surgically-prepared acetabulum ofthe patient. The acetabular prosthesis 240 may subsequently be implantedvia use of a impactor 248. To do so, the surgeon may impact the impactor248 (e.g., via use of a surgical hammer) to cause the acetabularprosthesis 240 to seed into the patient's surgically-preparedacetabulum. Of course, in other embodiments, other devices and tools maybe used to implant the acetabular prosthesis 240 using the guide pins215 as guides. Regardless, once the acetabular prosthesis 140 isimplanted, the guide pins 215 may be removed. It should be appreciatedthat because the acetabular prosthesis 240 is implanted using the guidepins 215 as a guides, the acetabular prosthesis 240 is implantedsubstantially at the predetermined location and orientation (e.g., atthe predetermined inclination and version angles).

Although the acetabular reamer guide 150 has been described above inregard to a customized patient-specific instrument, it should beappreciated that the acetabular reamer guide 150 may not be customizedto a specific patient in other embodiments. That is, in some embodimentthe acetabular reamer guide 150 may be configured to use on a variety ofpatients. For example, the acetabular reamer guide 150 illustrated inFIG. 16 may be embodied as a non-patient-specific orthopaedicinstrument. In such embodiments, the acetabular reamer guide 150 may bepre-operatively and/or intra-operatively adjusted by the surgeon toprovide the desired inclination and version angles for the acetabularprosthesis. As such, it should be appreciated that because theacetabular reamer guide 150 is adjustable in such embodiments, the guide150 may be used by the surgeon on a variety of patients and adjustedintra-operatively as desired by the orthopaedic surgeon.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the method, apparatus, and system describedherein. It will be noted that alternative embodiments of the method,apparatus, and system of the present disclosure may not include all ofthe features described yet still benefit from at least some of theadvantages of such features. Those of ordinary skill in the art mayreadily devise their own implementations of the method, apparatus, andsystem that incorporate one or more of the features of the presentinvention and fall within the spirit and scope of the present disclosureas defined by the appended claims.

The invention claimed is:
 1. A customized patient-specific orthopaedicinstrument for facilitating implantation of an acetabular cup prosthesisin a coxal bone of a patient, the customized patient-specificorthopaedic instrument comprising: a customized patient-specificacetabular reaming guide comprising a single monolithic componentincluding (i) a body having a longitudinal passageway definedtherethrough, (ii) a plurality of arms extending from the body, and(iii) a plurality of feet configured to contact a coxal bone of apatient, each foot of the plurality of feet being coupled to acorresponding arm of the plurality of arms, an acetabular reamersurgical tool configured to ream the patient's acetabulum, theacetabular reamer surgical tool including a body positioned in thelongitudinal passageway of the customized patient-specific acetabularreaming guide and secured thereto, wherein (i) each foot of theplurality of feet is non-movably fixed relative to the body based on (i)a predetermined degrees of version and inclination angles of theacetabular cup prosthesis when implanted in the patient's coxal bone,(ii) each foot of the plurality of feet includes a longitudinalpassageway defined therein that is sized to receive a bone guide pin,and (iii) each foot of the plurality of feet includes a bottom,bone-facing surface having a customized patient-specific negativecontour configured to receive a portion of the patient's coxal bonesurrounding the patient's acetabulum having a corresponding positivecontour, the customized patient-specific negative contour of each footbeing unique relative to the customized patient-specific negativecontour of every other foot to orient the acetabular reamer surgicaltool at the predetermined degree of version and inclination angles whenthe customized patient-specific acetabular reaming guide is engaged withthe patient's coxal bone.
 2. The customized patient-specific orthopaedicinstrument of claim 1, wherein: the body includes a bottom, bone-facingsurface and each foot of the plurality of feet includes a top surface,the bottom, bone-facing surface of the body being non-coplanar withrespect to a plane defined by the top surface of at least one of theplurality of feet.
 3. The customized patient-specific orthopaedicinstrument of claim 1, wherein: the body includes a bottom, bone-facingsurface and each foot of the plurality of feet includes a top surface,the bottom, bone-facing surface of the body and each top surface of theplurality of feet being coplanar with respect to each other.
 4. Thecustomized patient-specific orthopaedic instrument of claim 1, wherein:the body includes a bottom, bone-facing surface and the plurality offeet includes a first foot having a first top surface defining a firstplane and a second foot having a second top surface defining a secondplane, the bottom, bone-facing surface of the body, the first topsurface, and the second top surface are parallel and non-coplanar withrespect to each other.
 5. The customized patient-specific orthopaedicinstrument of claim 1, wherein: the body includes a bottom, bone-facingsurface and each foot of the plurality of feet includes a bottomsurface, the bottom, bone-facing surface of the body being positionedmedially with respect to the bottom surface of each foot of theplurality of feet when the customized patient-specific acetabularreaming guide is positioned in contact with the patient's coxal bone. 6.The customized patient-specific orthopaedic instrument of claim 1,wherein each foot of the plurality of feet has a longitudinal lengthdifferent from each other.
 7. The customized patient-specificorthopaedic instrument of claim 1, wherein the body includes a sidewalland each arm of the plurality of arms includes a bottom surface, whereineach bottom surface of the plurality of arms define an angle withrespect to the sidewall of the body that is different in magnitude withrespect to the angle defined by each other bottom surface of theplurality of arms.
 8. The customized patient-specific orthopaedicinstrument of claim 1, wherein an angle is defined between each arm ofthe plurality of arms with respect to another adjacent arm of theplurality of arms when viewed in a top plan view, each of the anglesbeing different in magnitude from each other.
 9. The customizedpatient-specific orthopaedic instrument of claim 1, wherein a distanceis defined between each foot of the plurality of feet and the body whenviewed in a top plan view, and each distance is different in magnitudethan each of the other distances defined between the body and each otherfoot of the plurality of feet.
 10. The customized patient-specificorthopaedic instrument of claim 1, wherein the plurality of armscomprises at least three arms extending from the body.